Commercial Building Sector Research Articles

An Energy Model for the Commercial Building Sector in Hong Kong

The building sector accounts for 15~40% of the energy consumption in cities and thus plays a significant role in promoting sustainable development. Hong Kong government established an ambitious target to reduce the energy intensity by 40% from the 2005 level by 2025, in which the energy efficiency in the commercial building sector is a key. This paper examines the role of human behavior, as well as regulations and technological advancements, in the commercial building sector in Hong Kong. Models in existing literature are not suitable for city-scale study due to the complexity in the commercial building sector in terms of the building scale and function, the energy systems and the technical characteristics, and the distribution of human behaviors among occupants. By developing an energy model accounting for those complexities, I first present the per m2 energy consumption in the commercial buildings in Hong Kong, which is much higher than the counterparts in OECD countries. I also evaluate the energy performance of various building regulations and technologies with the established model. My finding has direct implication for the Hong Kong government to allocate more resources in mobilizing citizens through various incentives and public education programs. My study bridges the gap between engineering simulations and the diversified real conditions in buildings for scholar conducting macroscopic studies and policy makers in cities.

Office building plug and light loads: Comparison of a multi-tenant office tower to conventional assumptions

Pressure to conserve energy in commercial buildings is increasing in order to meet nationwide greenhouse gas reduction targets. In the commercial building sector, multi-tenant buildings are common, where offices often receive yearly electricity bills based on their occupied floor area and not actual electricity consumption. This results in diffused responsibility for electricity consumption and little to no usage feedback or incentive to conserve energy. In this study, two office towers in Eastern Ontario installed submeters to accurately bill tenants for their electricity use. One year of tenant plug and light electricity use gives insights into and valuable high-resolution data for office electricity use across 32 submetered commercial building floors. Results find that commercial tenant electricity use, between tenants, is highly variable; that tenant controlled plug and light loads are lower than ASHRAE design values; and, that tenant plug loads are not fully shut off at night. Electricity use feedback is also assessed anecdotally for its impact on tenant energy use behaviour. The ideal level of submetering is discussed for the purpose of providing useful electricity use feedback to tenants.

Stock modelling of HVAC systems in Japanese commercial building sector using logistic regression

The stock of heating, ventilating and air-conditioning (HVAC) systems has not been well understood and its heterogeneity has been often ignored in urban-scale energy demand modelling and analysis although its significant influence on energy demand has been widely recognized. This study estimated the HVAC system stock being used in the Japanese commercial building sector. First, logistic regression analyses were conducted to develop a model to estimate the probability at which HVAC systems are selected when a building is constructed or renovated. The model was applied to building stock segments classified by its predictor variables. The total floor area served by HVAC systems was estimated as the product sum of the estimated HVAC system selection probability and the total floor area of each stock segment. The results showed that share of centralized HVAC systems has been decreasing. The electricity-driven HVAC systems was estimated to occupy 64% for cooling, 23% of which adopted heat storage systems especially in large-scale buildings. The results can be utilized to estimate the energy demand for HVAC of the commercial building stock while addressing the heterogeneity in the HVAC system stock, which would contribute to improving the accuracy of urban-scale energy demand models.

To Investigate the Influence of Building Envelope and Natural Ventilation on Thermal Heat Balance in Office Buildings in Warm and Humid Climate

India’s commercial building sector is witnessing robust growth. India continues to be a key growth market among global corporates and this is reflective in the steady growth in demand for prime office space. A recent trend that has been noted is the increase in demand for office spaces not just in major cities but also in smaller tier II and Tier III cities. Growth in the commercial building sector projects a rising trend of energy intensive mechanical systems in office buildings in India. The air conditioning market in India is growing at 25% annually. This is due to the ever increasing demand to maintain thermal comfort in tropical regions. Air conditioning is one of the most energy intensive technologies which are used in buildings. As a result India is witnessing significant spike in energy demand and further widening the demand supply gap. Challenge in India is to identify passive measures in building envelope design in office buildings to reduce the cooling loads and conserve energy. This paper investigates the overall heat gain through building envelope components and natural ventilation in warm and humid climate region through experimental and simulation methods towards improved thermal environmental performance.

Long-term carbon dioxide and hydrofluorocarbon emissions from commercial space cooling and refrigeration in India: a detailed analysis within an integrated assessment modelling framework

Quantification of greenhouse gas emissions is a critical research gap for space cooling and refrigeration applications in Indian commercial buildings. This is especially relevant as these services are expected to grow rapidly in future driven by economic growth and urbanisation. This paper focuses on these two applications which are highly energy and emission intensive, and quantifies their carbon dioxide (CO2) and hydrofluorocarbon (HFC) emissions through soft-linking a top-down model with a bottom-up approach. An integrated assessment modelling framework Global Change Assessment Model (GCAM)-IIM is used for modelling energy-related emissions under a business-as-usual scenario. In addition to CO2 emissions occurring from electricity use, cooling and refrigeration in commercial buildings emit another set of highly potent greenhouse gases, emanating from application of HFCs as coolant. HFCs substitute their ozone-depleting precursors in these applications. Countries across the world have agreed to phase down HFCs under the Montreal Protocol. Before we can analyse cost-effective options to bring down these emissions, it is important to quantify and assess the amount of emissions that could be avoided in the future. Our research sets up a baseline for carbon dioxide and HFC emissions from India for the commercial air-conditioning and refrigeration sectors and finds the potential HFC emission mitigation due to the Kigali Amendment. A detailed bottom-up modelling of these emissions is undertaken and it is found that, if unabated, the HFC emissions from commercial sector will surge from mere 1.8 million tonne (Mt) CO2e in 2015 to 211 Mt CO2e in 2050, whereas energy-related CO2 emissions from commercial air-conditioning and refrigeration will rise from 37 to 297 Mt CO2e in the same period. We also highlight the role of management practices and regulation for curbing HFC emissions which is especially relevant for the commercial building sector.

A review of fault detection and diagnostics methods for building systems

The current article provides a summary of automated fault detection and diagnostics studies published since 2004 that are relevant to the commercial buildings sector. The review updates a previous review conducted in 2004 and published in 2005, and it categorizes automated fault detection and diagnostics methods into three groups. The examples of automated fault detection and diagnostics in the primary category are selectively reviewed to identify various methods that are suitable for building systems and to understand the strengths and weaknesses of the methods. The distribution of studies based on each automated fault detection and diagnostics method and heating, ventilation, and air-conditioning system is also described. Researchers and industries can use the current article as a guideline for selecting an appropriate automated fault detection and diagnostics method.

Assessment of Potential Energy and Greenhouse Gas Savings in the Commercial Building Sector by Using Solar Energy for Air-conditioning Purposes

Australia currently faces significant increases in electricity prices. The owners and occupants of buildings are influenced by this change and alternative technologies are being investigated to reduce outgoing costs. The adoption of renewable and alternate solar technologies is gaining favour as reductions in technology component prices occur. The increase in population density and societies increasing expectation of conditioning spaces requires the continued investment in air-conditioning plant and equipment, generally at the expense of greenhouse gas emissions and high electricity consumption. This paper reviews the current potential of energy and greenhouse gas savings by using alternative solar-energy technologies for air-conditioning in commercial buildings. The economics of solar thermal and solar photovoltaic cooling systems will be discussed by calculation of the Levelised Cost of Cooling (LCOC) i.e. $/kWh of cooling. The paper will conclude the economic viability of solar thermal cooling in 2015 and provide comparison to findings based on 2011 economics to demonstrate the improving financial viability of solar-energy usage for air-conditioning. The paper further outlines constraints for adoption of solar thermal cooling in the commercial market and provides predictions on the potential greenhouse gas emissions savings that can be achieved from the adoption of alternate energy sources for air-conditioning.

Using information to close the energy efficiency gap: a review of benchmarking and disclosure ordinances

Building energy use accounted for 38 % of total US carbon dioxide (CO2) emissions in 2012, and roughly half of those emissions were attributable to the commercial building sector. A new policy that has been adopted in 15 US cities and one US county is a requirement that commercial and sometimes also multifamily residential building owners disclose their annual energy use and benchmark it relative to other buildings. We discuss these nascent policies, summaries of the data that have been collected so far, and how to evaluate whether they are having an effect on energy use and CO2 emissions. Missing or imperfect information is a contributor to the energy efficiency gap, the finding that many low-cost options for improving energy efficiency fail to be adopted. These new laws may be an important step in closing the gap in the commercial and multifamily building sectors, but careful evaluation of the programs will be essential.

Unlocking Energy Efficiency in Small Commercial Buildings through Mechanical Contractors

AbstractAlthough buildings smaller than 4,645 m2 account for nearly half of the energy used in U.S. commercial buildings, energy-efficiency programs to date have primarily focused on larger buildings. Stakeholder interviews conducted during a scoping study by Lawrence Berkeley National Laboratory (LBNL) indicated interest in energy efficiency from the small commercial building sector, provided solutions are simple and of low cost. To address this need, an energy management package (EMP) was developed to deliver energy management to small commercial buildings via HVAC contractors, because they already serve these clients and the transaction cost to market would be reduced. This energy-management approach is unique from, but often complementary to, conventional quality maintenance or retrofit-focused programs targeting the small commercial segment. This paper presents an overview of the EMP, the business model to deliver it, and preliminary demonstration findings from a pilot use of the EMP. Results from th...

Application of Fatty Acid Based Phase-Change Material to Reduce Energy Consumption From Roofs of Buildings

Buildings account for a significant portion of the total energy consumption in the U.S., especially the energy-inefficient commercial building sector. As part of the future path toward realizing net zero energy buildings, innovative energy-efficient technologies must be developed. In this study, the potential of phase-change material (PCM)-enhanced constructions to lower heating, ventilating, and air conditioning (HVAC) energy consumption in a commercial restaurant building was investigated. A commercially available fatty acid based PCM product was selected due to their promising thermal and chemical properties. Differential scanning calorimetry (DSC) was used in isothermal step mode to accurately measure the latent heat energy storage of the PCM. A U.S. Department of Energy (DOE) commercial reference building model with a PCM-enhanced ceiling was simulated using a finite-difference conduction heat transfer algorithm in EnergyPlus to determine the effects of the PCM on the building energy performance. It was found that, although the PCM-enhanced ceiling had a beneficial stabilizing effect on the interior surface temperature of the ceiling, the zone mean air temperatures were not significantly altered. As such, minimal HVAC energy savings were seen. Future work should focus on active PCM systems, which utilize heat exchanging fluids to discharge the PCM to remove the stored thermal energy of the PCM during the night in summer, overcoming the fundamental issue of the passive PCM system returning stored thermal energy back into the building.

Control-Oriented Thermal Modeling of Multizone Buildings: Methods and Issues: Intelligent Control of a Building System

The residential and commercial building sector is known to use around 40% of the total end-use energy and, hence, is considered to be the largest energy consumer sector in the world [1]. Approximately half of this energy is used for heating/cooling, ventilation, and air-conditioning (HVAC), and this usage is increasing 0.5?5% per year in developed countries [2]. The distribution of energy use percentages within the building for the United States is shown in Figure 1. This trend is similar for the rest of the world.

Modelling, Transient Simulation and Economic Analysis of Solar Thermal Based Air Conditioning System in Gujarat

Commercial building sector accounts for 8% of the total electricity consumption in India. Cooling activities (HVAC) in commercial buildings consume 55% of the total energy utilized. Consequently, CO2 emissions from conventional buildings in India were estimated to be 98 metric tonnes of CO2 per million ft2 in 2014. Solar thermal air conditioning can be the solution to these demands and can contribute to about 15% to 20% of India’s total oil consumption thereby reducing the dependence on fossil fuels. Hence, the main objective of the work is to model and simulate a solar absorption cooling system for GERMI office building located in Gandhinagar, Gujarat, India, using the transient simulation software ‘TRNSYS’. Cooling load estimation and comfort conditions required for the building were determined based on ASHRAE standards. Evacuated tube collectors were selected because of its market availability, ease of manufacturing and proven technology. Single effect absorption chiller was used because of its commercial availability. The effects of storage tank volume, collector area and collector slope were also investigated for parametric optimization. The results of the simulation and parametric analysis are analyzed and presented in the paper.

Embodied and operational energy in buildings on 20 Norwegian dairy farms – Introducing the building construction approach to agriculture

Embodied energy in barns is found to contribute to about 10–30% of total energy use on dairy farms. Nevertheless, research on sustainability of dairy farming has largely excluded consideration of embodied energy. The main objectives of this study were to apply an established model from the residential and commercial building sector and estimate the amount of embodied energy in the building envelopes on 20 dairy farms in Norway. Construction techniques varied across the buildings and our results showed that the variables which contributed most significantly to levels of embodied energy were the area per cow-place, use of concrete in walls and insulation in concrete walls. Our findings are in contrast to the assumption that buildings are similar and would show no significant differences. We conclude that the methodology is sufficiently flexible to accommodate different building design and use of materials, and allows for an efficient means of estimating embodied energy reducing the work compared to a mass material calculation. Choosing a design that requires less material or materials with a low amount of embodied energy, can significantly reduce the amount of embodied energy in buildings.

Analysis of US commercial buildings’ energy efficiency programs

Purpose – The purpose of this paper is to investigate relationships between five energy efficiency programs and electricity intensities in the US commercial buildings sector. Design/methodology/approach – Regression methods analyze state-level secondary data from 2006 through 2009 to identify significant energy program drivers of electricity efficiency. Findings – Combined, the five programs studied account for approximately nine percent reduction in commercial electricity intensity. Practical implications – Outcomes will inform stakeholders’ decision-making regarding adoption or continuation of energy programs. Social implications – Electricity efficiency gains will help reduce negative environmental aspects and the present dependence on foreign oil. Originality/value – Very little research has considered the impact of multiple programs on commercial electricity efficiency within their complex implementation environment.

Application of calcium chloride as an additive for secondary refrigerant in the air conditioning system type chiller to minimized energy consumption

One way to resolve the energy problem is to increase the efficiency of energy use. Air conditioning system is one of the equipment that needs to be considered, because it is the biggest energy user in commercial building sector. Research currently developing is the use of phase change materials (PCM) as thermal energy storage (TES) in the air conditioning system to reduce energy consumption. Salt hydrates have been great potential to be developed because they have been high latent heat and thermal conductivity. This study has used a salt hydrate from calcium chloride to be tested in air conditioning systems type chiller. Thermal characteristics were examined using temperature history (T-history) test and differential scanning calorimetry (DSC). The test results showed that the thermal characteristics of the salt hydrate has been a high latent heat and in accordance with the evaporator temperature. The use of salt hydrates in air conditioning system type chiller can reduce energy consumption by 51.5%.

Optimal distributed energy resources and the cost of reduced greenhouse gas emissions in a large retail shopping centre

Abstract This paper presents a case study on optimal options for distributed energy resource (DER) technologies to reduce greenhouse gas emissions in a large retail shopping centre located in Sydney, Australia. Large retail shopping centres take the largest share of energy consumed by all commercial buildings, and present a strong case for adoption of DER technologies to reduce energy costs and emissions. However, the complexity of optimally designing and operating DER systems has hindered their widespread adoption in practice. This paper examines and demonstrates the value of DER in reducing the carbon footprint of the shopping centre by formulating and solving a multiobjective optimisation problem using the Distributed Energy Resources Customer Adoption Model (DER-CAM) tool. An economic model of the shopping centre is developed in DER-CAM using on-site-specific demand, tariffs, and performance data for each DER technology option available. Four key optimal DER technology investment scenarios are then analysed by comparing: (1) solution trade-offs of costs and emissions, (2) the cost of reduced emissions attained in each investment scenario, and (3) investment benefits with respect to the business-as-usual scenario. The analysis shows that a moderate investment in combined cooling, heat and power (CCHP) technology alone can reduce annual energy costs by 8.5% and carbon dioxide-equivalent emissions by 29.6%. A larger investment in CCHP technology, in conjunction with on-site solar photovoltaic (PV) generation, can deliver nearly 72% reductions in emissions at a 47% increase in total energy costs. The study demonstrates the effectiveness and flexibility of this type of modelling approach for the analysis, design, and ongoing assessment of new DER technologies under changing market conditions, supporting a more robust adoption of DER technologies in the commercial building sector.

Customer-side electricity load management for sustainable manufacturing systems utilizing combined heat and power generation system

Customer-side electricity load management can effectively improve the reliability of electricity grid and reduce the cost of electricity for customers. Combined heat and power (CHP) generation systems have been considered a promising method to implement electricity load management and have been widely applied in commercial and residential building sectors. Recently, the benefit of CHP application in electricity load management in industrial sector has also been gradually recognized. On-site generated electricity by a CHP system can be utilized to support the operation of industrial equipment and thus the cost of electricity purchased from the grid can be reduced. In this paper, we focus on the utilization of CHP in electricity load management for industrial manufacturing systems to examine the benefits regarding cost savings for the manufacturers. The optimal schedule for both the manufacturing and the CHP systems under a Time-of-Use (TOU) electricity tariff can be identified by minimizing the electricity billing cost and CHP operation cost under the constraint of production throughput. Mixed-Integer Nonlinear Programming (MINLP) formulation is developed to model this scheduling problem mathematically. Particle Swarm Optimization (PSO) is used to find a near optimal solution for the problem with a reasonable computational cost. A numerical case study is used to illustrate the effectiveness of the proposed method.

Can Benchmarking and Disclosure Laws Provide Incentives for Energy Efficiency Improvements in Buildings?

Building energy use accounted for 38 percent of total US carbon dioxide (CO2) emissions in 2012, and roughly half of those emissions were attributable to the commercial building sector. A new policy that has been adopted in 10 US cities and one US county is a requirement that commercial and sometimes also multifamily residential building owners disclose their annual energy use and benchmark it relative to other buildings. We discuss these nascent policies, preliminary analyses of the data that have been collected so far, and how to evaluate whether they are having an effect on energy use and CO2 emissions. Missing or imperfect information is a contributor to the energy efficiency gap, the finding that many low-cost options for improving energy efficiency fail to be adopted. These new laws may be an important step in closing the gap in the commercial and multifamily building sectors, but careful evaluation of the programs will be essential.

The Manual of Low Energy Office Design

With the energy crisis and energy-related environmental issues increasingly severe, how to solve them has become an important part of sustainable development. As a significant consumer in the field of energy, commercial buildings consumed enormous energy worldwide. Therefore, implementing low energy design in commercial building sector has become the necessary measure and effective way to save energy consumption. This manual is to develop the skills of sustainability together with design factors and principles to achieve low energy office design through consider the aspects of internal and external factors of the selected office as well as employ renewable energy. It is not only suitable for the selected office, but for the common modern offices as well. Meanwhile, it could also provide design suggestions and as a guideline for designs and architects.

A pathway for net-zero energy buildings: creating a case for zero cost increase

To have market relevance and gain widespread market adoption, zero energy buildings (ZEBs) will need to be designed and constructed cost-effectively, and preferably without additional costs. An approach was developed to create low-energy buildings without additional construction costs such that it yielded innovation in building technology and integration by the market. A case study of the implementation of this method is presented to provide a data point that ZEBs can be built with zero cost increase. Documenting cost-control best practices and packaging those strategies for adoption by the commercial building sector will help make the business case for ZEBs for mainstream construction and promote market uptake of the innovative technologies and design approaches needed. The holistic implementation of cost-control strategies will enable ZEBs to be designed and constructed on a typical budget. The current state of ZEB economics is evaluated and a path forward is proposed for greater market penetration of ZEBs. By demonstrating how to combine ZEB technologies and design approaches into an overall efficiency package that can be implemented at minimal (zero, in certain cases) incremental capital cost, the domain of ZEB design and construction can be expanded from a niche market to the commercial construction mainstream.